Projects actions are by default dependent — each action is not available to work on until the previous action has been completed. This is how the Next Actions list is able to display the next action for a project.
Sometimes there are actions that can be completed independently. In other words, in any order.
Define which actions in your projects can be done in any order using an Independent Action Group (IAG).
The IAG behaves as a single, dependent action within the list of Project Actions.